Negative & Positive Pressure
A Slow combustion fireplace requires oxygen to complete the combustion cycle, oxygen is a natural component of the atmosphere. In order for the fireplace to work correctly it needs to draw, which requires positive pressure.
The Oxygen and consequently the air used in the combustion process must be replaced to create that positive pressure.
Outside Air Kit
In older homes, this is created by air being drawn into the house via window and or door gaps, electrical outlets and other non-sealed penetrations such as recessed lighting.
In modern homes, heavy insulation and the sealing of gaps in doors and windows creates an air tight and energy efficient home - this has a negative effect on the air pressure within the house which prevents the fire from drawing and working correctly.
VisionLINE Air Flue Kit
Other outside influences such as extraction systems for bathrooms and kitchens also create this negative pressure.
To overcome this an outside air kit may be fitted, this is a secondary air pipe fitted directly to the fire to feed the for air independent of the room.
The other alternative would be to use our revolutionary VisionLINE AIR flue system which feeds air to the fire via the same flue used to carry exhaust fumes to the outside. This gives you flexibility of install and a more efficient fire.
At Visionline fireplaces, we use a kiln brick inside our units due to its thermal mass and durability.
Typically, European style fireplaces sold in Australia use a material called Vermiculite which is a thermally efficient and lightweight compressed ceramic material. The problem with this material when used in fireplaces is that it is fragile and prone to breaking if the user is not careful when placing wood into the fire to re-fuel.
Kiln bricks are clay based, extremely dense and heavy and best suited in situations where impact with a dense Australian hardwood is likely.